This invention relates to wavelength multiplexers and demultiplexers for communication utilizing electromagnetic waves as a carrier.
The demand for compact, simple and dependable multiplexers and demultiplexers is especially high for single-mode fiber optical communication systems. It is well known that optical communication with single-mode fibers has enormous potential in terms of communication capacity. In order to fully utilize this potential, time multiplexing and wavelength (frequency) multiplexing are necessary. Wavelength multiplexing is considered especially promising because it does not require fast switching, the speed of which may impose an ultimate limit on the full utilization of the available bandwidth in single-mode fiber communication. Conventional wavelength multiplexers are reviewed in detail by W. J. Tomlinson in Applied Optics, Vol. 16, No. 8, pp. 2180-2194, August, 1977. Conventional multiplexers/demultiplexers require an unguided collimated beam and are quite bulky.